Electric switch-operating mechanism



c. F. SCHWENNKER ELECTRIC SWITCH OPERATING MECHANISM July 16,1929.

Filed July 19, 1928 Inventor ChafiLes F.Schwenr-mc-n" log y HLS Attorney.

Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

CHARLES F. SCHWENN'KER, OF SCIIENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OFN'EW YORK.

ELECTRIC SWITCH-OPERATING MECHANISM.

Application filed July 19,

My invention relates to mechanism for operating electric switches, and particularly to mechanism for operating switches at high speed such, for example, as is shown in the Tritle Patent 1,560,440, November 3, 1925. It is an object of my invention to provide an improved switch operating mechanism of the character disclosed in the aforesaid patent in which a greater opening speed of the switch is produced and in which the blow of the closing movement is cushioned.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing, Figs. 1, 2 and 3 illustrate one embodiment of my invention respectively in open circuit position, in an intermediate position and in closed circuit position.

I have chosen to illustrate my invention as applied to a liquid break switch having a pivotally mounted movable contact although it should be understood that it is by no means limited to such a switch. The fixed contact 1 and the movable contact 2 are shown immersed in insulating liquid 3, such for example as oil, contained in the tank 4 having the cow'er 5. The movable contact 2 is carried by the lever 6 which is fulcrumed at 7 and which is operated by the link 8. Floating lever 9 is pivoted at one end to link 8 and at the other end to the arm 10 at the point 11. Arm 10 is secured to a shaft j ournalled in an auxiliary housing secured to the cover, a suitable opening being provided in the cover through which the arm projects. Rod 12 which is adapted to connect with any suitable operating mechanisn'n not shown, such for example as a solenoid connects by another arm on the'shaft, outside of the chamber which communicates with the interior of the switch. Lever 9 at an intermediate point thereof connects through link 13 with the pivoted armature 14 of the electromagnetic releasable retaining means 15. This means preferably is of the type disclosed in the above mentioned Tritle Patent although other suitable retaining means may ct if de ired. For cushioning the er when the same moves to posh point 21.

1928. Serial No. 294,001.

tion I have shown the buffer 16 which may comprise several layers of felt. The powerful switch opening spring 18 is shown attached at one end thereof to lever at the point of connection therewith of the link 13 and at the other end to the fixed point 19. Switch closing spring 20 is shown attached at one end to pivot pin 11 between lever 9 and arm 10 and at the other end to the fixed To control the movements of the floating lever 9 I connect with it the dash pot 22 which as shown in the drawing is double-acting and comprises the cylinder'23 having one or more openings 24 in its intermed ate portion and the piston 25 arranged to slide past the openings so as to be checked at either end of its stroke. For convenience I attach the cylinder and piston of the dash pot to the same members to which the 010s pression spring at the other end suitably supported from a fixed part of the switch frame. Roller 31 mounted on the pivot connection between lever 9. and link 8 rolls on the upper side of arm 28 during certain portions of the switch opening movement. v

The operation of the apparatus embodymg my invention is as follows: Considering the apparatus to be in the open circuit position illustrated by Fig. 1, a pull on operating rod 12 rocks arm 10, lever 9 and armature 14 against the. force of springs 20 and 18. Upon reaching the pole piece of the electromagnet 15 the armature is retained thereby, the parts then being in the position illustrated by Fig. 2. During this movement the piston of the dashpot has made one traverse of the cylinder and in so doing first expelled the liquid therein through the holes formed in the wall of the cylinder and then the holes at Wlliich time it excited t. clamp inn attest upon "turthee 'iteevifiximi the 1nechanis1n. lVhen the mechanism is operated with considerable force, as for leasing example by a solenoid, and the movement of the parts is not checked at the end of the stroke, the rebound of the armature 14. is sufiicient to disengage with the magnet. Upon reaching the position shown in Fig. 2 the actuating force is removed from rod 12 whence spring rocks lever 9 and arm 10 to the position shown in Fig. 3, the center of lever 9 being retained in the raised position by the armature 14. In this movement of lever 9 the switch is closed and the dash pot piston again traverses the cylinder. In so doing it again expels the liquid through the openings in the cylinder and in passing on beyond them exerts a strong damping effect upon any further movement of the parts. The dash pot thus effectively cushions the blow or shock of the forceful engagement of the cooperating switch contacts which it has been found set up vibrations sufficient in certain cases, particularly Where butt contacts such as shown are used to cause the release of the retaining means.

Opening of the switch is produced by rethe electromagnetic retaining means. This may, for example, be effected in response to a predetermined overload on the circuit controlled by the switch in the .manner explained in the aforesaid Tritle I not shown in the drawing since they form no part of the present invention. Such a switch is capable of interrupting a power current of many thousand ampcres within one half cycle of the occurrence of a predetermined overload or short circuit.

11011 the parts are in the position shown in Fig. 3 the dash pot piston is not at the extreme lower end of the cylinder so that the floating lever upon being released is capable of movement under the influence of spring 18 either bodily downward or if otaly about the pivot pin 11. It will be apparent from an inspection of the drawing that for the greatest opening speed of the movable switch contact the lever 9 should have the aforesaid pivotal movement. New this pivotal movement is assured by the dash pot 22, forat the beginning of the opening stroke, see Fig. 3, the dash pot piston is already in the lower portion of the cylinder, that is, it is past the openings 24'. Any ordinary burning away of the switch contacts in service is automatically compensated by pivotal movement of lever 9 about its connection with link 13. The dash pot thus in the last named function governs the movement of the mechanism when the switch is released to cause the contacts to separate at the highest speed possible. The opening movement of, the switch lever and associated parts is cushioned by the roller engaging the buffer arm 28 and the armature 1% engaging the buffer 16.

I have chosen the particular embodiment described above as illustrative of my invention and it will be apparent that'various modifications may be made without departing from the spirit and scope of my invention which modifications I aim to cover by' the appended claims.

hat I claim as new and desire to secure by Letters Patent of the United States, is

1 Switch operating mechanism comprising a floating member having a connection at one portion thereof with a switch to be operated, operating means connected to the member at another portion thereof, releasable retaining means for said member, and a dash pot connected with the member at that portion thereof to which the operating means is connected whereby upon the release of the retaining means the switch is operated with the maximum speed.

2. Switch operating mechanism comprising a floating lever, means connecting one end thereof with a switch to be operated, operating means connected to the lever at the other end thereof, a second operating means connected to the lever at an intermediate point thereof, releasable retaining means for the lever and a dash pot connected with the lever at said other end thereof.

3. Switch operating mechanism comprising a lever, a connection between one portion thereof and a switch to be operated, operating means connected to another portion thereof, releasable retaining means connected to an intermediate portion of the lever and means comprising a dash pot operatively connected to the lever for cushioning the closing movement of the switch and for controlling the movement of the lever when the'same is released by the releasable means.

1. Switch operating mechanism comprising a floating lever, a connection between one end thereof and aswitch to be operated, op erating means connected with the other end of the lever, a releasable retaining means connected with an intermediate portion of the lever, an operating spring also connected with an intermediate portion of the lever and a dash pot connected with said other end of the lever whereby the closing movement of the switch is cushioned and in the opening-movement of the switch the lever is caused to fulcrum about its said other-end.

5. Switch operating mechanism compristhereof, an electromagnetic releasable retaining means connected with the lever at an intermediate oint thereof a switch closin spring connected with the lever at said other end thereof, a switch opening spring connected with the lever at an intermediate point thereof and a dash pot connected with the 10 lever at said other end thereof.

In witness whereof, I have hereunto set my hand this 18th day of July, 1928.

CHARLES F. SGHWENNKER. 

